The technical field of this invention concerns electric feed devices which can be started by immersion in a liquid.
Many electric devices can be started by immersion in a liquid that use either a battery which is directly started by the liquid, or a pressure sensitive switch. In the first instance, a battery is used which is electrolytic to sea water, so that it only produces a current when it is submerged. However, even during storage, this kind of battery can display undesirable discharge features for firing a detonator, for instance, and they are mainly comprised of silver, which increases the cost of such devices. Furthermore, we cannot envisage defusing such a battery. In the other instance, switches, described for instance in French Pat. No. 2 008 865, are used which include a capillary tube in the bottom of which two electrodes are placed. Contact between those two electrodes is achieved at a particular immersion depth, enabling passage of a weak current that must be amplified with a semi-conductor device to make the ancillary device operate. The main disadvantage in this device rests in the existence of dielectric currents, stemming from the semi-conductor, that cross the device to be started on the one hand and that discharge the battery after a certain storage period on the other. This switch lacks reliability and does not make it possible to store signalling buoys, mines outfitted with the latter, etc., for a sufficiently long period.
The purpose of this invention is to provide an electric feed device which overcomes the previously mentioned disadvantages by providing a device which can start as soon as it is immersed in a liquid, in which there is no dielectric current and the operation of which is interrupted upon the disappearance of the immersion liquid.